A man is in custody and assisting police after a woman was found dead outside an apartment block in Perth today.

Police said an unidentified man, believed to be known to the woman, approached paramedics about the body on the Grand Boulevard in Joondalup by paramedics at 9.45am AWST (11.45am AEST).

Authorities are investigating the cause of the woman’s death and whether there are any suspicious circumstances.

WA Police Detective inspector Jayd Morawski.WA Police Detective inspector Jayd Morawski. (9News)

The woman has not yet been formally identified at this stage.

Earlier today, WA Police detective inspector Jayd Morawski urged the unidentified man to contact police.

“We want to provide a full picture, so we know exactly what occurred, so we can provide answers to the family and provide answers to the state coroner,” Morawski said.

“There is a conversation required, there are answers that need to be given and he can provide those answers, so we’d like him to do that on his own volition.

“Ultimately, we have a lot of resources and a lot of technology that we can deploy to find this person.

“We know who he is and the best thing he can do is hand himself in to police.”

In an update later this evening, police said a 35-year-old was in their custody and assisting officers with their investigation.

Police do not believe there is any threat to the wider community.

“This is an isolated matter and as such, we don’t think the community is at any risk,” Morawski said.

Police are also seeking CCTV and dashcam footage from the Grand Boulevard between 9.30am and 9.45am today.

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